Transducers used in ultrasonic equipment



July 21, '1959 B. CARLIN 2,896,099

TRANSDUCERS USED IN ULTRASONIC EQUIPMENT Filed April 4, 1955 Ti .4-A INVENTOR. j 1 Baum/v C44 4 I Y United States Patent TRANSDUCERS USED IN ULTRASONIC EQUIPMENT Benson Carlin, Fair Lawn, NJ., assignor to Alcar Instruments, Inc., Little Ferry, N.J., a corporation of New Jersey Application April 4, 1955, Serial No. 499,024

2 Claims. (Cl. 310-26) My invention relates to improvements in transducers used in ultrasonic equipment in which the resonant element is a combination of strip and rod and the overall length is the resonant length. The object of my improvement is to cut down losses and bring up ultrasonic vibration by the use of strip for a section of the head. These losses are due to currents which normally flow in the solid material. In the past it has been common to make heads either from a solid piece of rod or completely from laminations. The unit made exclusively from a solid rod has certain mechanical advantages but the losses are comparatively great. The object of this invention is to retain the mechanical advantages of the rod While getting the electrical advantages of the strip.

For a better understanding of the invention, as well as other objects and features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:

Fig. 1 is a schematic diagram of a transducer rod in accordance with one embodiment of the invention.

Fig. 1A is an end view of the rod shown in Fig. 1.

Fig. 2 is a schematic diagram of a transducer rod in accordance with another embodiment of the invention.

Fig. 2A is an end view of the rod shown in Fig. 2.

Fig. 3 is a schematic diagram in accordance with yet another embodiment of the invention.

Fig. 3A is an end view of the rod shown in Fig. 3.

Fig. 4 is a schematic diagram of still another embodiment of the invention.

Fig. 4A is an end view of the rod shown in Fig. 4.

Figure one shows the drawing of a typical head of this type. This is a group of laminations 1 bonded together to form a half of the head 2 supported in the center by a ring or other support. 3 represents a solid rod.

The head of a transducer is solid and the unit will vibrate as a Whole. Figure 2 shows the support of a vibrating rod 4 in the center by a sleeve 5 which can then be supported near one end of the rod by a tube 6. This allows the rod to be inserted into the coil and for the rod itself to be interchangeable in the coil. In the past, rods have not been interchangeable because of the inability to support them near the center.

These rods may have ends Which are either square or various shapes, such as pointed, tapped, etc., which are well known and obvious changes to the basic rod.

In ultrasonic soldering, the article being soldered is heated by an external source, the rod serving to vibrate the article at an ultrasonic rate, thereby obviating the need for flux. However, it is sometimes advisable to heat the tip of the rod sufficiently whereby the tin is not solidified by it. One means of doing this is by the use of a heater unit mounted on the transducer head and radiating into the tip. This is of course an obvious application of the well known soldering iron. However a novel means in accordance with the invention is by choosing the size of the Wire in the head which carries the ultrasonic energy to be such that the voltage drop in it will contribute to the heating of the tip.

'It is sometimes necessary to have a vibrating rod to stir a large amount of material and to make it interchangeable with smaller rods. One such unit is shown in Figure 3. This consists of a rod 7 of a smaller diameter terminating in a disc or plate 8 of relatively large diameter. The unit vibrates as a whole with plate 8 acting as a piston. Therefore, as regards cross section of the ultrasonic waves, the rod appears to have a greater diameter than it actually does and yet the support can be made identical with a rod of smaller cross sections.

Another type of rod is shown in Figure 4. In this use, the head of the rod 7 is a cup made of the same material as the rod. In this unit the resonant length of the rod is the overall length including the cup.

I claim:

1. An ultrasonic soldering transducer comprising a magnetostrictive vibratory metal rod, one-half sectional length of which is constituted by a group of laminations, the other half of which is solid and is bonded to said one-half to form a resonant unit, and a coil surrounding said rod, said coil being wound of wire in which the voltage drop when current flows therein produces sulficient heat to raise the temperature of said rod to a point sulficiently high to prevent solidification of solder vibrated by said rod.

2. An ultrasonic soldering transducer comprising a magnetostrictive vibratory metal rod, and a coil surrounding said rod, said coil being wound of wire in which the voltage drop when current flows therein produces sufiicient heat to raise the temperature of said rod to a point sufficiently high to prevent solidification of solder vibrated by said rod.

References Cited in the file of this patent UNITED STATES PATENTS 1,693,806 Cady Dec. 4, 1928 1,750,124 Pierce Mar. 11, 1930 1,982,341 Hitchcock Nov. 27, 1934 2,116,522 Kunze May 10, 1938 2,170,206 Mason Aug. 22, 1939 2,478,207 Robinson Aug. 9, 1949 2,553,251 Gutterman May 15, 1951 2,635,388 Peyches et al. Apr. 21, 1953 2,636,998 Davis et a1. Apr. 28, 1953 2,723,386 Camp Nov. 8, 1955 FOREIGN PATENTS 739,901 Germany Oct. 7, 1943 

